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smsinville's avatar
smsinville
Explorer
Oct 08, 2016

Refrigerator bypass electronics for direct AC power

I have a dometic RML8555 refrig. It worked on AC and DC, but not propane. Took into a shop and they said it needed to electronics panel at $600+, but the panel was on nationwide backorder ... would be weeks. I said I'd pick up trailer and return when part was in. Now when I plug it in to 110 at home,the refrigerator is TOTALLY DEAD. Nothing on the eyebrow panel. Called service tech at repair shop, said it was fine when they had it (sure it was!). Don't want to bother taking the trailer in again for now. Question. IS THERE A WAY TO "BYPASS" THE ELECTRONICS FOR IT TO WORK ON 110? In order words, how can I get it to work on 110 (which I assume means converted to 12v) by running converted current directly to the refrigerator bypassing the electronics panel.
  • Thanks for the feedback. I'm still a little nervous about bypassing all electronics and safety on/off switches to wire directly to a 110v line. But Doug, you seem to be pretty sure that it would not damage anything. I could certainly put that 110v line on a timer and set the timer to cycle it off for 30 minutes every 3 or 4 hours. Also, someone mentioned the 12v refrigerator fuse. It may be that this thing does not work on 110v OR on 12v because a fuse is blown. All fuses in the converter panel are OK (those are ALL 15v fuses by the way). Would there normally be a 12v line fuse near the refrigerator, visible when I open the outside access panel? If there is one there, I'm not finding it. Seems like there would/should be one. Thanks again to all for helping me to think through this.
  • MEXICOWANDERER wrote:
    This is a "I am wondering" question and not a challenge. When I operated absorbsion refrigerators down here, they would light off and go to High Burner" 24/7
    The cooling units never burned out. As a pure emergency measure I did install a mechanical AC refrigerator thermostat with the thermocouple about 6" away from the cooling fins. Being it was 2,000 miles to the border there was little choice in the matter. It lasted as long as I was in the area which was about two and a half months as I recall.
    The hazard of cooling unit burnout is something new to me. When I was fighting the Norcold it was almost 30 years ago. Have things changed?


    The poster that warned about overheating. Yes, it is possible. NOT LIKELY even bypassing the controls. Both Dometic and Norcold have overtemp discs on the burner casing cover that will shut off 12 volt power IF the unit overheats. The unit will overheat ONLY if the rear backside ventilation is blocked. But wiring direct will bypass that 12 volt safety control. A LOT of refers operate 24/7 because of high outside ambient temps and opening and closing the doors. The refers NEVER reach to set temp because of this. They do NOT overheat or cause a failure unless they leak or operate off spec level or the ventilation gets blocked. Doug
  • This is a "I am wondering" question and not a challenge. When I operated absorbsion refrigerators down here, they would light off and go to High Burner" 24/7
    The cooling units never burned out. As a pure emergency measure I did install a mechanical AC refrigerator thermostat with the thermocouple about 6" away from the cooling fins. Being it was 2,000 miles to the border there was little choice in the matter. It lasted as long as I was in the area which was about two and a half months as I recall.
    The hazard of cooling unit burnout is something new to me. When I was fighting the Norcold it was almost 30 years ago. Have things changed?
  • I would check the fuses first you have a 12volt fuse in your fuse box and another in the control box on the rear of your fridge. There may also be 12volt wires disconnected by the tech that worked on it. Either or both of the fuses may have been shorted out been there done that.
  • smsinville wrote:
    I have a dometic RML8555 refrig. It worked on AC and DC, but not propane. Took into a shop and they said it needed to electronics panel at $600+, but the panel was on nationwide backorder ... would be weeks. I said I'd pick up trailer and return when part was in. Now when I plug it in to 110 at home,the refrigerator is TOTALLY DEAD. Nothing on the eyebrow panel. Called service tech at repair shop, said it was fine when they had it (sure it was!). Don't want to bother taking the trailer in again for now. Question. IS THERE A WAY TO "BYPASS" THE ELECTRONICS FOR IT TO WORK ON 110? In order words, how can I get it to work on 110 (which I assume means converted to 12v) by running converted current directly to the refrigerator bypassing the electronics panel.


    That fridge REQUIRES 12V to operate the control board (and "brow board"), if lights not lighting most likely the dealer has disconnected or removed the 12V connection.

    As far as "bypassing" the control board.. No, not safely if you are planning to operate more than just for "testing purposes"..

    Hooking up the 120V heater element directly to 120V AC will totally eliminate ALL temp controls AND CRITICAL SAFETY CONTROLS!!!

    This will potentially and rather easily OVER HEAT THE COOLING UNIT FATALLY DAMAGING A EXTREMELY EXPENSIVE PART OF YOUR FRIDGE!!!

    Not to mention causing a potential FIRE HAZARD if cooling unit overheats and cracks.

    Dealer price on the control board is way over the top too expensive and there IS a potential source for a AFTERMARKET control board.. Someone already mention Dinosaur boards, they don't directly sell to the public but you can easily find dealers which will sell one to you. They are often much cheaper than OEM but also highly regarded as better made.

    For now, IF YOU MUST camp, USE A ICE CHEST AND ICE (or use bottles of ICE in your fridge) or take a small dorm fridge with you...
  • 1. Do as the other poster stated. Wire the 120 element direct. Then use a simple plug in xmas type timer to turn the element on and off. probably run for 20 hours and then off for 4 hours until you get a handle on the time really needed to prevent freezing the lower section.
    2. Yes, your refer is a Euro and Canadian refer. Not even available in the USA. So, Dometic does not have the parts readily available. We have been waiting on the control module since July on a 8555. Are you POSITIVE the refer has 12 volts supply to the back input connection? Doug
  • The fridge does not have a 120V to 12V converter. If it's totally dead, that usually implies that it isn't getting 12V power. It may be the board, but more likely (since it was somewhat working previously) is that the 12V supply is interrupted.

    Is the battery disconnect switch turned off? Is the 12V fuse for the fridge circuit good? Is/are the 12V fuse(s) in the fridge itself OK?
  • The heating elements in the boiler tube are AC
    Disconnect and connect to pigtail with a male plug
    Then plug into an extension cord, or the 120v duplex out let behind fridge

    One problem... No control..it will be on full-time 24/7 , you might turn the while fridge into a freezer

    People do this for testing
    I would recommend doing this, and then leaving the RV
    No temp control no safeties except the circuit breaker for the outlet

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